"It won't kill you, I promise," says Wattbike's Matt Moran, introducing me to the sleek lines of his company's hi-tech exercise bike at a swanky south London gym. OK, it has some zippy-looking red-and-white stripes, but what's so special about it? The answer is simple: it's what the professionals use. Developed by British Cycling and Wattbike, it has been a big hit with top British cyclists since development began in 2002.

It has, says Moran, been carefully designed to feel exactly like a road bike (I'm surprised to learn that's not the case with most stationary bikes). But the killer app is the software, which users can download free from the company's website. It gives an incredibly detailed breakdown of your cycling technique. There is, says Moran, a surprising amount of ignorance about good cycling technique, even among top cyclists, and the bike is designed to help anyone to improve their cycling, and train more effectively.

I strap on a heart-rate monitor, hop on and start cycling, doing a standard 20-minute warm-up, starting at a cadence of 90 revs per minute and gradually upping the pace. It feels very fast to me, but, says Moran is what I should be aiming for on the road. "I do have trouble with my knees," I admit. He shrugs as if to say he's not surprised. After about 10 minutes the sweat is pouring off. "People using it at home have to put a towel underneath to stop the carpet rotting," says Moran.

I can immediately see what he means: the flywheel-driven action feels very natural (people can fit their own saddles and pedals). But I'm bamboozled by the whirling blobs appearing on his laptop that is hooked up to the bike. In fact they show the points where I'm exerting the most pressure on the pedals. I'm producing a figure-eight shape, typical of cyclists with dreadful technique, meaning I'm getting almost no force at the top and bottom of the revolution. What I should be aiming for now is a "peanut" showing that I'm exerting a more steady amount of pressure. The top cyclists produce a "sausage" profile. I snigger. "Yes," says Moran wearily. "We get a lot of that, as you can imagine."

After my exhausting "warm-up", we do a three-minute "test" with me pedalling at a sustainable level (in my case at about 100 rpm) using the best technique I can. If I was going to embark on a long-term programme, the computer would then spit out my heart-rate training zones and a profile of my technique, and then I would use the website to set up a tailored programme.

Moran says the company works hard at its presence on Twitter and Facebook. (Apparently people like posting the results of their workout on Twitter.) Former footballer Lee Dixon tweets about it a lot (the company doesn't pay for personal endorsements) and Moran reckons Wattbike has shifted several bikes on his recommendation alone. I'm assuming that well-off middle-aged blokes are his biggest market but he says that although he doesn't have exact figures, his guess is that about 40% of customers are women, and it's particularly popular with triathletes.

At £1,995, though, they're not for the casual user, although you can also rent them directly from the company at £60 a month, and they're becoming more common in gyms. Moran also says that if people want to try one, they should contact the company directly, which will try to help them track one down to try in their neighbourhood.

I liked it at lot, although admittedly having an expert on hand helped. And although I'm probably not quite ready to fork out a couple of grand, I would certainly use one if it was in my gym. Maybe I need to. As I stagger off the saddle, Moran sizes me up. "Perhaps I should have pushed you harder at the end," he says. "But I was worried by how much you were sweating during the warm-up."